I had 4 ivory inlays put in the forearm of my Coker and it turned out great. You're looking at the cost of the inlay and probably a refinish. About 100 to 150 but that's just based on my experiences.
Yes, it is possible. A friend of mine had ivory inlays and ringwork added to a Predator sneaky pete. Pat Diveney did the work. It turned out great and the price was reasonable. I would contact him and see what he says.